Temperatures dipped into the 40s°F today, prompting additional layers for
the crew. When experiencing lower temperatures, we take additional precaution
with the birds to help prevent ‘cold stress’. Most species that are prone to
cold stress are smaller in body size such as kinglets, gnatcatchers, and some
warblers. We band these species first, and even transport them inside our
jackets to help keep them warm. A whole new meaning to having a down jacket!
Cool air temperatures don’t put migration on hold; we banded 91 new birds
today by the time it’d warmed to the low 60s°F when we finished for the day. Of
the 18 unique species we handled today, a pair belonging to the same species
was a delightful surprise.
While the Mourning Dove is abundant across the United States, it is an
uncommon capture at our station; the pair banded today brings our total to
three for the season thus far. Their larger size and powerful wings in
conjunction with the smaller mesh size of our nets (designed for smaller
passerines) make it difficult for the dove to become entangled at first contact
and have proven easy for escape once in the net. As luck would have it, two
crew members were in the right place at the right time and were able to ensure
the safe and effective capture of these two beautiful birds:
Mourning Doves
(AHY female pictured left, and HY male pictured right)
In addition to being a cool capture, these birds provided an excellent
chance to compare both juvenile and adult plumages. Below you can observe both
the after hatch year (bottom) and hatch year (top) wing. A characteristic that
immediately identifies a hatch year wing is the presence of buffy tips on one
or more feathers. Our hatch year bird presents many buffy tipped feathers while the after hatch year below has none. Additional clues that identify a
bird as a hatch year include the presence of molt limits [the contrast between
new (replaced) and old (unreplaced) feathers] amongst the primary feathers. In
our hatch year dove, you can see a clean contrast between the older juvenile feathers,
which are worn and brown (left of the arrow), and that of the new adult feathers, which appear
fresh and gray (right of the arrow). In comparison the adult wing exhibits uniform gray feathers; molt limits can be found in adult wings but the color will
be uniform.
Aging Comparison of Mourning Doves Using Wings
(AHY pictured bottom left, HY pictured top right)
- Claire
NEW BIRDS
2 Mourning
Dove
1
Yellow-billed Cuckoo
5 Eastern
Phoebe
1
Blue-headed Vireo
6 House Wren
2
Golden-crowned Kinglet
4
Ruby-crowned Kinglet
1 Hermit
Thrush
25 Gray
Catbird
1 Northern
Mockingbird
19
Yellow-rumped Warbler (Myrtle)
6 Palm Warbler
(Western)
6 Common
Yellowthroat
1 Northern
Waterthrush
1 Painted
Bunting
1 Northern
Cardinal
1 Song
Sparrow
8 Swamp
Sparrow
RECAPTURES
1 House Wren
1
Ruby-crowned Kinglet
9 Gray
Catbird
1 Northern
Mockingbird
2 Northern
Cardinal
BANDING STATS
# of Birds
Banded: 91
# of
Recaptures: 14
# of
Recaptures: 18
Effort:
103.5 net-hours
Capture
Rate: 101.4 birds/100 net-hours
# of
Nets: 20
